Observation of H₂O in a strongly lensed Herschel-ATLAS source at z = 2.3
The Herschel survey, H-ATLAS, with its large areal coverage, has recently discovered a number of bright, strongly lensed high-z submillimeter galaxies. The strong magnification makes it possible to study molecular species other than CO, which are otherwise difficult to observe in high-z galaxies. Am...
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2011 |
| País: | México |
| Institución: | Instituto Nacional de Astrofísica, Óptica y Electrónica |
| Repositorio: | Repositorio Institucional del INAOE |
| Idioma: | inglés |
| OAI Identifier: | oai:inaoe.repositorioinstitucional.mx:1009/1868 |
| Acceso en línea: | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/1868 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Inspec/Galaxies: high-redshift info:eu-repo/classification/Inspec/Galaxies: starburst info:eu-repo/classification/Inspec/Galaxies: active info:eu-repo/classification/Inspec/Infrared: galaxies info:eu-repo/classification/Inspec/Submillimeter: galaxies info:eu-repo/classification/Inspec/Radio lines: galaxie info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/21 |
| Sumario: | The Herschel survey, H-ATLAS, with its large areal coverage, has recently discovered a number of bright, strongly lensed high-z submillimeter galaxies. The strong magnification makes it possible to study molecular species other than CO, which are otherwise difficult to observe in high-z galaxies. Among the lensed galaxies already identified by H-ATLAS, the source J090302.9-014127B (SDP.17b) at z = 2.305 is remarkable because of its excitation conditions and a tentative detection of the H₂O 2₀₂2-1₁₁ emission line (Lupu et al. 2010, ApJ, submitted). We report observations of this line in SDP.17b using the IRAM interferometer equipped with its new 277–371 GHz receivers. The H₂O line is detected at a redshift of z = 2.3049 ± 0.0006, with a flux of 7.8 ± 0.5 Jy km s⁻¹ and a FWHM of 250 ± 60 km s⁻¹. The new flux is 2.4 times weaker than the previous tentative detection, although both remain marginally consistent within 1.6σ. The intrinsic line luminosity and ratio of H₂O(2₀₂−1₁₁)/CO(8−7) are comparable with those of the nearby starburst/enshrouded-AGN Mrk 231, and the ratio I(H₂O)/L is even higher, suggesting that SDP.17b could also host a luminous AGN. The detection of a strong H₂O 2₀₂−1₁₁ line in SDP.17b implies an efficient excitation mechanism of the water levels that must occur in very dense and warm interstellar gas probably similar to Mrk 231. |
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